Define possible adaptive options based on the assessment of territorial and social vulnerability

Transcription

1 Climate change impacts on water availability in three Mediterranean watersheds of Catalonia (NE Spain) Diana Pascual, Eduard Pla (CREAF) Roger Milego (ETC-SIA) SCARCE 2nd annual conference INDEX 1.The project 2.Background 3.Data and methods 4.Results 5.Discussion and conclusions

2 The project MAIN AIMS: Assess territorial vulnerability of three diverse Mediterranean watersheds in Catalonia with regard to the main effects of global change on water availability Define possible adaptive options based on the assessment of territorial and social vulnerability The project has been developed during three years by four different research institutions with an interdisciplinary approach. Study areas Siurana Fluvià Tordera Barcelona Study areas are three medium size watersheds: Fluvià (977 mm, 13 ºC) Tordera (819 mm, 14 ºC) Siurana (589 mm, 13 ºC)

3 INDEX 1.The project 2.Background 3.Data and methods 4.Results 5.Discussion and conclusions Background Mediterranean basin might become one of the most vulnerable areas in Europe regarding climate change at the end of the Century Winter Summer Mediterranean basin might suffer a significant decrease in runoff at the end of the Century. Source: IPCC, Christensen et al. and Alcamo et al. 27

4 Background CLIMATE: OBSERVED TEMPERATURE TRENDS ( ) 18. Annual mean temperature (ºC) Siurana Fluvià A 1.9 ºC temperature increase since 1979 has been monitored at the three watersheds Barcelona Tordera 29 Background Annual precipitation (mm) Annual precipitation (mm) CLIMATE: OBSERVED PRECIPITATION TRENDS FLUVIÀ Castelló d'empúries,67 mm/ year FLUVIÀ Castelló d'empúries,67 mm/year No significant changes in annual precipitation... Precipitation changes in March Precipitation trends in March (mm/year) from Precipitation changes in March (mm/year)...but significant changes in certain months Significant area at 95% confidence level

5 INDEX 1.The project 2.Background 3.Data and methods 4.Results 5.Discussion and conclusions INDEX 1.The project 2.Background 3.Data and methods 3.1. SWAT Calibration and Validation 3.2. Climate projections 3.3. Socioeconomics scenarios 4.Results 5.Discussion and conclusions

6 SWAT model Water balance model Distributed and continuous hydrological model coupled to a GIS interface SWAT estimates superficial and sub-superficial flow, aquifers recharge, erosion, sediments deposition and movement, SWAT calibration and validation Model calibration: Based on stream flow series from 12 gauging stations and climatic series from 23 meteorological stations Available data: (25 years) Calibration and validation: Daily time step, 3-4 years periods Objectives: simulated hydrograph similar to observed one, mean flow values and total contributions similar between simulated and measured data, Adequate values of statistics (Nash and Sutcliffe efficiency coefficient (NSE) and RMSE-observations standard deviation ratio (RSR))

7 SWAT calibration and validation Daily stream flow (m3/s) 3 Fluvià Daily stream flow (m3/s) 2 Tordera Daily stream flow (m3/s) 3 Siurana Observed data SWAT simulated data Daily data SWAT calibration and validation Monthly stream flow (m 3 /s) 7 Fluvià 6 Measured data SWAT simulated data Monthly data

8 INDEX 1.The project 2.Background 3.Data and methods 3.1. SWAT Calibration and Validation 3.2. Climate projections 3.3. Socioeconomics scenarios 4.Results 5.Discussion and conclusions Climate projections at global scale CO 2 emissions global scenarios (IPCC): B1, A2 CO 2 atmospheric (ppm) A1fi A2 B1 B2 Observed Years A2 B1 Atmospheric and Oceanic General Circulation Model (AOGCM): ECHAM5 Dynamic downscaling (SMC): high temporal and spatial resolution (6 h and 15 km), period and reference period Source: IPCC (Intergovernmental Panel on Climate Change), SMC (Meteorological Service of Catalonia)

9 Climate projections at regional scale FUTURE PRECIPITATION TRENDS Annual precipitation (mm) FUTURE TEMPERATURE TRENDS Fluvià 26-23: -2.4 to -3% : to -15.3% B : -7.6 to -9.6% : -24 to -28.3% A2 Scenario A2 Reference Five-years running mean Reference Scenario B1 Five-years running mean scenario B1 Five-years running mean scenario A2 Source: SMC 21 (Meteorological Service of Catalonia) Climate projections at regional scale FUTURE PRECIPITATION TRENDS FUTURE TEMPERATURE TRENDS 2 Mean temperature (ºC) Fluvià 26-23: +.51 to +.58 ºC : +2.2 to +2.3 ºC A B :+.26 to +.47ºC : +3.4 to 3.6 ºC Scenario B1 Scenario A2 Reference Five-years running mean Reference Five-years running mean scenario B1 Five-years running mean scenario A2 Source: SMC 21 (Meteorological Service of Catalonia)

10 Precipitation spatial distribution PRECIPITATION REDUCTION AT XXI CENTURY (mm/decade) A2 climate scenario predicts stronger and significant reductions, specially on headwaters Source: SMC 21 (Meteorological Service of Catalonia) Precipitation trends (mm/decade) Significant area at a 95% confidence level INDEX 1.The project 2.Background 3.Data and methods 3.1. SWAT Calibration and Validation 3.2. Climate projections 3.3. Socioeconomics scenarios 4.Results 5.Discussion and conclusions

11 SUSTAINABLE SCENARIO TRENDING SCENARIO Socioeconomic scenarios How will the territory be in 23...?... IF WE DEVELOP ADAPTIVE MEASURES? Socioeconomic background Moderate economic growth Moderate population growth Containment of energy consumption Population (thousands of people) Water demand (hm3/year) Population (thousands of people) P Water demand (hm3/year)... IF WE PROJECT THE TRENDS FROM THE PAST 2 YEARS? Socioeconomic background Fast economic growth Fast population growth Intensive use of fossil fuels Globalisation Source: ACCUA from ACA and IDESCAT data Socioeconomic scenarios Land cover scenarios for 23 Land Change Modeler (Idrisi) land cover change analysis and prediction software

12 Socioeconomic scenarios Land cover scenarios for 23 ACCUA scenarios SCENARIO CATALONIA 23: TRENDING SCENARIO SUSTAINABLE SCENARIO Land cover scenarios 23 Vulnerability of main agricultural classes Main land cover flows Land Change Modeler Extension - IDRISI Urban sprawl Analysis and prediction of changes. Analysis of change explanatory variables. sostenible Socioeconomic scenarios Land cover scenarios for 23 Trending Sustainable Fluvià Tordera Siurana

13 INDEX 1.The project 2.Background 3.Data and methods 4.Results 5.Discussion and conclusions Results at short term (26-23) RELATIVE STREAM FLOW CHANGES RESPECT (%) Stream flow variation at headwater % % % % Fluv Tord Siu Stream flow variation at river mouth % % % % Fluv Tord Siu Generalized stream flow reduction, more severe at A2 scenario (- 2 to -29 %) Fluvià and Tordera: Differences between socioeconomics scenarios are not relevant Strong effect of forest in water balance Siurana: The increase of the water demands (irrigation) amplify the effects of climate change. In Fluvià watershed, the highest reductions are expected in the headwater.

14 Results at long term (276-21) RELATIVE STREAM FLOW CHANGES RESPECT (%) Stream flow variation at headwater % Stream flow variation at river mouth % % % Fluv Tord Siu Fluv Tord Siu Generalized stream flow reduction, more severe at A2 scenario (-33 to -48 %) Stronger reductions are expected at Fluvià headwater (-31 to -48 %) Results ECOLOGICAL FLOW VARIATION (FLUVIÀ) Number days Q < Q ecologic By the end of the Century, the number of days per year with stream flow lower than ecological flow will increase (more than 9 days in A2) Increase number days Q < Q ecologic < >

15 Results CHANGES IN CLIMATIC DISTRIBUTION OF FOREST SPECIES Beech at Fluvià Oak at Tordera Species from humid areas (beech, oak, scots pine) trend to marginal conditions Holm oak at Siurana These same species in currently marginal areas may be compromised their viability. Sclerophylls and evergreen species (Holm oak, Aleppo pine) extend their suitability to higher areas Unsuitable Marginal Source: BIOCLIM model Suitable Results FIRE RISK (DROUGHT CODE. CANADIAN METEREOLOGIC INDEX) Number of days / year with DC > 8 (EXTREM RISK) Number of days/year DC> Number of days/year DC> Number of days/year DC>8 Risk fire increase may aggravate forest vulnerability

16 Results IRRIGATION REQUERIMENTS FOR CORN IN FLUVIÀ LLEGENDA Necessitatsde reg per mesos (mm) Irrigation requirements (mm/month) Juny June Juliol July Agost August Setembre September October Octubre Irrigation requirements LLEGENDA (mm/month) Necessitatsde reg per mesos (mm) June Juny July August Juliol September Agost October Setembre Octubre Irrigation requirements in some actual crops, which are rarely or not currently irrigated, may be highly increased at the end of the XXI Century. Source: IRTA INDEX 1.The project 2.Background 3.Data and methods 4.Results 5.Discussion and conclusions

17 Discussion and conclusions A strong alteration on water dynamics is expected during the XXI Century: 22% to 48% reduction of stream flow, more severe in the A2 scenario than in the B1 Reductions especially severe in the wetter headwaters (Fluvià and Tordera) Socioeconomic scenarios for 23 did not show contrasted differences, except in Siurana watershed where the full development of the Catalan Irrigation Plan affects water availability. Greater vulnerability of wet watersheds in northern Catalonia, where present ecosystems are more sensitive to changes in environmental conditions Results highlight the strong impact of climate change on regional water resources and stress the need for incorporating these analyses into adaptive management in the Mediterranean region Thank you! accua@creaf.uab.cat